class Back {
  static easeIn(e, t, n, r) {
    let i = 1.70158;
    return n * (e /= r) * e * ((i + 1) * e - i) + t;
  }
  static easeOut(e, t, n, r) {
    let i = 1.70158;
    return n * ((e = e / r - 1) * e * ((i + 1) * e + i) + 1) + t;
  }
  static easeInOut(e, t, n, r) {
    let i = 1.70158;
    return (e /= r / 2) < 1
      ? (n / 2) * e * e * (((i *= 1.525) + 1) * e - i) + t
      : (n / 2) * ((e -= 2) * e * (((i *= 1.525) + 1) * e + i) + 2) + t;
  }
}

export default Back;
